自定义复合控件[4]引发回递事件

using System;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.ComponentModel;

namespace csMathControl
{
    /**//// <summary>
    /// 引发回递事件
    /// </summary>
    [DefaultProperty("Text"), 
        ToolboxData("<{0}:AlertButtonThree runat=server></{0}:AlertButtonThree>")]
    [DefaultEvent("Click")]
    public class AlertButtonThree : System.Web.UI.WebControls.WebControl,IPostBackEventHandler
    {
        private string text;
    
        [Bindable(true), 
            Category("Appearance"), 
            DefaultValue("")] 
        public string Text 
        {
            get
            {
                return text;
            }

            set
            {
                text = value;
            }
        }
        //-----------------------事件
        public event EventHandler Click;
        /**//// <summary> 
        /// 将此控件呈现给指定的输出参数。
        /// </summary>
        /// <param name="output"> 要写出到的 HTML 编写器 </param>
        protected override void Render(HtmlTextWriter output)
        {
            //output.Write(Text);
            output.Write("<h3>Render控件,引发回嫡事件的</h3>");
            output.AddAttribute("value","用户自定义控件");
            output.AddAttribute("type","button");
            output.AddAttribute("onclick","javascript:alert('你好,小美女呵呵');"+Page.GetPostBackEventReference(this));//这个是关键
            output.RenderBeginTag("INPUT");
            output.RenderEndTag();
        }
        
        IPostBackEventHandler 成员#region IPostBackEventHandler 成员

        public void RaisePostBackEvent(string eventArgument)
        {
            OnClick(EventArgs.Empty);
        }

        #endregion
        protected virtual void OnClick(EventArgs e)
        {
            if(Click!=null)
                Click(this,e);
        }
    }
}